Temperature, pressure,
moisture, and wind measurements are reported hourly at the surface (most are
usually made 2 meters above the ground).
77:
Temperature.
68: Dewpoint.
998: Pressure, to the
nearest tenth of a millibar. Add either a 10 or 9 in front based on which would
bring the value closer to 1000. The pressure here is 999.8 millibars (mb).
-03: Pressure tendency the
last 3 hours, to the nearest tenth of a millibar. The pressure here has fallen
.3 mb the last 3 hours.
Middle Circle (filled in w/ mostly black): Cloud
cover. It's mostly black showing that this station is mostly cloudy.
Technically, this represents a broken sky with 7/8 of the sky covered with clouds.
Black line, extending from circle: Wind
barb. It points to where the wind is coming from. The wind here is from the
southwest, hence a southwest wind. The two lines extending represent 20 knot
winds with each line representing 10 knots.
Symbol between 77 and 68: This
is the present weather field and in this case shows that there is a
thunderstorm occurring at the station.
Symbol next to -03: That
line is the pressure tendency. The 1st hour the pressure was steady, then fell
the last two hours.
Triangle (with a dot above it): Previous
weather, or the weather one hour ago. In this case it was a light rain shower.
How
does the upper air station model differ from the surface station model?
─
Temperature is given in Celsius
─
Dewpoint depression is given not dewpoint
temperature
─
Altitude of the pressure surface is given
instead of pressure
─
Cloud cover is not noted
─
Circles indicating station locations are often
omitted
